Study on image registration of simultaneous imaging polarization system

Detection technology of imaging polarization has potential applications in target detection and remote sensing, with this technology the polarization state of light emitted from and/or reflected from scene can be measured. Simultaneous Imaging Polarization (SIP) is a new imaging polarization technology, which can avoid false polarization effects in time-sequential polarization detection system caused by the motion of the platform or target. The detection system can simultaneously obtain polarization intensity images of the same target among 0, 45, 90 and 135 on the same detector. Consequently, there is mis-registration among these four images, though the registration parameters are constant after the system is assembled. So, in order to obtain accurate polarization information of the detected target, registration accuracy of four images must reach 0.1 pixel. The polarization image registration method which was based on the spatial and frequency domain cross-correlation was presented. Firstly, pretreatment of these four images was prepared for image registration. Secondly, cross- correlation in spatial domain was used to achieve the pixel level of image registration. At last, cross-correlation in frequency-domain was used to achieve the sub-pixel level image registration. In order to validate the accuracy of this registration method, many experiments have been done and its registration accuracy can meet this SIP system's requirement.